acumen vs shallowness

acumen

noun
  • Quickness of perception or discernment; penetration of mind; the faculty of nice discrimination. 

  • A bony, often sharp, protuberance, especially that of the ischium. 

  • A sharp, tapering point extending from a plant. 

shallowness

noun
  • the property of being shallow 

How often have the words acumen and shallowness occurred in a corpus of books? (source: Google Ngram Viewer )